1,678 research outputs found
Ectoparasites and Other Arthropod Associates of the Hairy-tailed Mole, \u3ci\u3eParascalops Breweri\u3c/i\u3e
A total of 33 taxa of ectoparasites and other associates was taken on seven individuals of the Hairy-tailed Mole, Parascalops breweri, from New York and New England. The most abundant form was the glycyphagid mite, Labidophorus nearcticus
Ectoparasites and Other Arthropod Associates of Some Voles and Shrews From the Catskill Mountains of New York
Reported here from the Catskill Mountains of New York are 30 ectoparasites and other associates from 39 smoky shrews, Sorex fumeus, 17 from 11 masked shrews, Sorex cinereus, 11 from eight long-tailed shrews, Sorex dispar, and 31 from 44 rock voles, Microtus chrotorrhinus
Emergency Conservation Program (ECP)
The Energy Conservation Program (ECP) was established to provide cost share to eligible agricultural producers to rehabilitate farmland and conservation practices damaged by natural disasters and provide cost share assistance during periods of severe drought
Integral Kernel Operators in the Cochran -Kuo -Sengupta Space.
This dissertation contains several results about integral kernel operators in white noise analysis. The results found here apply to the space of test functions and generalized functions that were constructed in the paper of Cochran, Kuo, and Sengupta, based on a sequence of numbers &cubl0;an&cubr0; infinityn=0. . We shall prove results about existence, restrictions, and extensions of integral kernel operators based on the conditions on &cubl0;an&cubr0; infinityn=0. contained in the paper of Kubo, Kuo, and Sengupta. Also, we shall prove an analytic property and growth condition of the symbol of a continuous operator in CKS space. Our results are similar to results Chung, Ji, and Obata have found for the CKS space
Ionization behavior of the histidine residue in the catalytic triad of serine proteases
α-Lytic protease is a homologue of the mammalian serine proteases such as trypsin, chymotrypsin, and elastase, and its single histidine residue belongs to the Asp-His-Ser catalytic triad. This single histidine residue has been selectively enriched in the C-2 carbon with 13C. Magnetic resonance studies of the chemical shift and coupling constant (1Jch) behavior of this nucleus as a function of pH suggest that the imidazole ring is neutral above pH 5 and therefore that the group which is known to ionize with pKa near 6.7 must be the aspartic acid residue.
Implications of these new pKa assignments for the catalytic mechanism of serine proteases are discussed and include the absence of any need to separate charge during catalysis. The histidine residue plays two roles. (a) It insulates the aspartic acid from an aqueous environment and accordingly raises its pKa. (b) It serves as a bidentate base to accept a proton from the serine at one of its nitrogens and concertedly transfer a proton from its other nitrogen to the buried carboxylate anion during formation of the tetrahedral intermediate
Characterization of devices, circuits, and high-temperature superconductor transmission lines by electro-optic testing
The development of a capability for testing transmission lines, devices, and circuits using the optically-based technique of electro-optics sampling was the goal of this project. Electro-optic network analysis of a high-speed device was demonstrated. The project involved research on all of the facets necessary in order to realize this result, including the discovery of the optimum electronic pulse source, development of an adequate test fixture, improvement of the electro-optic probe tip, and identification of a device which responded at high frequency but did not oscillate in the test fixture. In addition, during the process of investigating patterned high-critical-temperature superconductors, several non-contacting techniques for the determination of the transport properties of high T(sub c) films were developed and implemented. These are a transient, optical pump-probe, time-resolved reflectivity experiment, an impulsive-stimulated Raman scattering experiment, and a terahertz-beam coherent-spectroscopy experiment. The latter technique has enabled us to measure both the complex refractive index of an MgO substrate used for high-T(sub c) films and the complex conductivity of a YBa2Cu3O(7-x) sample. This information was acquired across an extremely wide frequency range: from the microwave to the submillimeter-wave regime. The experiments on the YBCO were conducted without patterning of, or contact to, the thin film. Thus, the need for the more difficult transmission-line experiments was eliminated. Progress in all of these areas was made and is documented in a number of papers. These papers may be found in the section listing the abstracts of the publications that were issued during the course of the research
Subband gap carrier dynamics in low-temperature-grown GaAs
Measurements of the carrier relaxation dynamics in low-temperature-grown GaAs have been made with a femtosecond-resolution, time-resolved pump-probe technique using a subband-gap probe-beam wavelength. The transient absorption and index of refraction changes have been analyzed using a relaxation model with up to four different excited state populations. The carrier recombination time within the midgap trap states is found to be longer than the subpicosecond free-carrier trapping time. Two time scales are observed for the recombination rate, one of a few picoseconds and one of hundreds of picoseconds, indicating the presence of at least two different trap states for the free-carriers in this material. © 1997 American Institute of Physics.  Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71168/2/APPLAB-70-15-1998-1.pd
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